There have been various developments within the prior art, where attempts have been made, to provide wheels capable of providing controlled motion of a vehicle in any direction. For example, U.S. Pat. No. 7,641,288 issued Jan. 5, 2010 (Baker et al.) discloses an omnidirectional wheel that when mounted on the four corners of a frame and independently driven allow for omnidirectional movement of the mounting frame. The omnidirectional wheel design allows the use of two identical stampings or molded bases with key holes and locating posts diametrically opposed, assembled back to back with elastomeric or rubber outer rollers mounted in between at an angle to the axis of rotation.
U.S. Pat. No. 6,547,340 issued Apr. 15, 2003 (Harris) discloses an omnidirectional wheel for an omnidirectional vehicle that exhibits constant ride height, low vibration, and reduced maximum ground contact pressure. The omnidirectional wheel consists of a wheel assembly rotatably connected to the omnidirectional vehicle chassis. The wheel assembly includes a hub on which free spinning rollers are rotatably mounted at an angle to the wheel axis. Another patent issued to Harris is U.S. Pat. No. 6,796,618 disclosing a method for designing an omnidirectional wheel.
U.S. Patent No. 2002/0153205, published Oct. 24, 2002 (Zinanti) discloses an omnidirectional wheel having a frictional bias which favors a forward and backward motion over a side-to-side motion. The omnidirectional wheel includes a frame having an upper portion for affixing the frame to an under-side of a weight bearing surface, at least two walls, and a central cavity defined between the side walls for receiving at least one spherical wheel, and at least two wheel bearings connected in axial alignment to the side walls for rotation of the wheel about a fixed axis.
U.S. Pat. No. 4,223,753, issued Sep. 23, 1980 (Bradbury) discloses an apparatus for producing or measuring omnidirectional motion of the apparatus upon a relatively smooth but not necessarily planar surface and/or for producing or measuring omnidirectional movement of the surface relative to the apparatus. The transport device includes a frame and at least two wheels having peripheral rollers, the wheels rotating about non-parallel axes. Any desired movement of the device relative to a given surface can be achieved be appropriate rotational inputs to the wheels.
U.S. patent application Ser. No. 13/261,181 published Jul. 19, 2012 (Liddiard) discloses an omnidirectional wheel having a rim for mounting a tire, a hub for rotatably attaching the wheel to a vehicle, and a means for connecting the rim and hub. The rim of the wheel has a part which is rotatably connected to the hub and which, when radially rotating around the hub, engages the surface of the tire mounted on the rim for rolling the tire on the rim. A tire for use with the omnidirectional wheel is also disclosed.
There are known issues surrounding the prior art designs of omnidirectional wheels. In particular, the prior art wheel designs which rely on many small wheels or rollers arranged in a substantially circular structure forming a larger wheel are known to have limited transit speeds due to uneven ride and vibrations, especially under heavy load. Further, the use of such wheels may be severely limited on certain surfaces and under adverse weather conditions by virtue of an uneven contact with the surface.
Moreover, the designs involving angles and many small wheels appear overly complex and consist of many parts which may be prone to mechanical failure or require heavy maintenance. Additionally, such wheels appear to have restrictive loads due to many connecting joints and frictional bias. Accordingly, it may be desirable to provide an omnidirectional wheel which is simple in design and is adequate and ready for use in a vast range of vehicles without significant changes to the existing chassis or drive mechanism of the vehicle.